The present invention relates to a valve actuator system for controling or actuating valves, above or under water.
It is known to control valves hydraulically, pneumatically and mechanically. Such controls are used, for instance, in offshore hydrocarbon production. A disadvantage of these controls is that all the necessary energy for the movement of the shut-off members of the valves must be supplied over long distances, from either a fixed or a floating installation.
Another disadvantage, in particular of hydraulic systems, is that these systems are very complicated and expensive, especially when used in connection with emergency shut-off valves which are rarely used. The hydraulic systems also are uneconomical since much maintenance work must be done without daily use of the systems.